The present invention relates to a press for punching and cutting, respectively trimming, plate-shaped workpieces, especially sheet metal workpieces.
For the production of planar metal sheet parts in small series as required for instance in the electro-industry or for the construction of apparatus and similar fields of technical endeavor, numerically controlled turret punching presses or punching presses with only one punching tool are used since long time. If the sheet metal parts are relatively small, a plurality thereof are often combined to a large sheet and punched in such a manner that the programming expenditure is reduced and the output increased. This working procedure has, however, the disadvantage that, after the punching, the large sheet has to be subdivided into the corresponding punched sheet metal parts. For this purpose there are two possibilities:
1. The large sheet is subdivided in hammer shears.
This method is, however, difficult to carry out when, as is quite often the case, special requirements with respect to the exactness of the sheet metal parts are requested. First of all, it is already difficult to produce exactly parallel cuts and to produce cuts which are normal to each other and further to locate the prior punched hole or holes exactly in proper position to the outer contour of the thus-produced metal sheet parts.
2. It is also possible to separate the parts on the turret punch press subsequent to the punching of the metal sheet. For this purpose separating tools in form of small rectangular punches are used. Disadvantageous in such construction is that only relatively small separating tools may be used and in addition two stations of the turret press are necessary for the required cuts in two directions normal to each other.
In order to avoid the above-mentioned difficulties there is also a machine on the market which is in the form of a numerically controlled cutting press in which in one stroke a cut in two directions normal to each other may be produced. This cutting press is provided with a coordinate table for feeding the sheet metal to the cutting knives. This cutting press has the advantage, as compared to the above-mentioned hammer shears, that it will work with greater precision and this press will also operate considerably faster as in a process in which the cutting is carried out on the turret punch press, since considerably longer cutting knives may be used. However, this machine is fully separated from the punching press and furthermore this machine is relatively expensive. With regard to the total production process of the above-mentioned sheet metal parts there exists in all above-mentioned machines the disadvantage that the sheets which are punched in a punch press, especially a turret punch press, must be removed from this press and then transported to the respectively used cutting machine to be reclamped therein and to be subsequently cut into individual sheet metal parts or trimmed. This procedure requires, on the one hand, the additional expenditure for a separate machine, which is especially disadvantageous in the production of small series of metal sheet parts, and on the other hand, it increases considerably the necessary expenditure of labor and time, while still causing some problems as to the exactness of the produced metal sheet part since the same have to be clamped, properly oriented, in two different machines.